Are Replanted Floodplain Forests in Southeastern Australia Providing Bird Biodiversity Benefits?

Revegetation of massively altered landscapes for multiple benefits (including biodiversity and ecological function) has accelerated over the past two decades in southern Australia. However, much of the action has been conducted piecemeal, with little apparent strategy. We consider here replanted woodlands on the floodplain of the Murray River, northern Victoria, Australia. All are small in area (<18 ha) and recent (<30 years) and have been planted with appropriate trees and shrubs. We employed a scoring system devised to rapidly measure bird breeding success and linked these results to in-site and landscape variables. Most bird species using the replantings were those that are tolerant of much disturbed landscapes and of open country. Factors related to breeding success were different for each of the six species for which inferences could be made, indicating that it would be difficult to simultaneously plan for all species. Birds characteristic of the major forest floodplain remnants were poorly represented and there was little evidence of their breeding in the replantings. The value of the replanted sites for birds is marginal at present, although it may be that the sites are still too young to have realized their usefulness for species of conservation concern. We believe that most production landscapes in this region have far too little native vegetation to support the many species that are declining, and more strategic planning is necessary to overcome these deficiencies.     

Rapid Nitrate Loss and Denitrification in a Temperate River Floodplain

Nitrogen (N) pollution is a problem in many large temperate zone rivers, and N retention in river channels is often small in these systems. To determine the potential for floodplains to act as N sinks during overbank flooding, we combined monitoring, denitrification assays, and experimental nitrate (NO₃⁻ -N) additions to determine how the amount and form of N changed during flooding and the processes responsible for these changes in the Wisconsin River floodplain (USA). Spring flooding increased N concentrations in the floodplain to levels equal to the river. As discharge declined and connectivity between the river and floodplain was disrupted, total dissolved N decreased over 75% from 1.41 mg l⁻¹, equivalent to source water in the Wisconsin River on 14 April 2001, to 0.34 mg l⁻¹ on 22 April 2001. Simultaneously NO₃⁻ -N was attenuated almost 100% from 1.09 to <0.002 mg l⁻¹. Unamended sediment denitrification rates were moderate (0–483 μg m⁻² h⁻¹) and seasonally variable, and activity was limited by the availability of NO ₃⁻ -N on all dates. Two experimental NO₃⁻ -N pulse additions to floodplain water bodies confirmed rapid NO₃⁻ -N depletion. Over 80% of the observed NO ₃⁻ -N decline was caused by hydrologic export for addition #1 but only 22% in addition #2. During the second addition, a significant fraction (>60%) of NO₃⁻ -N mass loss was not attributable to hydrologic losses or conversion to other forms of N, suggesting that denitrification was likely responsible for most of the NO₃⁻ -N disappearance. Floodplain capacity to decrease the dominant fraction of river borne N within days of inundation demonstrates that the Wisconsin River floodplain was an active N sink, that denitrification often drives N losses, and that enhancing connections between rivers and their floodplains may enhance overall retention and reduce N exports from large basins.     

Spatial Patterns of Movement of Dung Beetle Species in a Tropical Forest Suggest a New Trap Spacing for Dung Beetle Biodiversity Studies

A primary goal of community ecologists is to understand the processes underlying the spatiotemporal patterns of species distribution. Understanding the dispersal process is of great interest in ecology because it is related to several mechanisms driving community structure. We investigated the mobility of dung beetles using mark-release-recapture technique, and tested the usefulness of the current recommendation for interaction distance between baited pitfall traps in the Brazilian Atlantic Forest. We found differences in mean movement rate between Scarabaeinae species, and between species with different sets of ecological traits. Large-diurnal-tunneler species showed greater mobility than did both large-nocturnal tunneler and roller species. Our results suggest that, based on the analyses of the whole community or the species with the highest number of recaptured individuals, the minimum distance of 50 m between pairs of baited pitfall traps proposed roughly 10 years ago is inadequate. Dung beetle species with different sets of ecological traits may differ in their dispersal ability, so we suggest a new minimum distance of 100 m between pairs of traps to minimize interference between baited pitfall traps for sampling copronecrophagous Scarabaeinae dung beetles.     

Effectiveness of a Newly Created Oxbow Lake to Mitigate Habitat Loss and Increase Biodiversity in a Regulated Floodplain

In 2005, an oxbow lake was constructed in a degraded floodplain area of the Ebro River (NE Spain) to mitigate habitat loss. In this study, we address the effectiveness of this restoration project through the analysis of the macroinvertebrate community that colonized the newly constructed lake, in comparison with a nearby natural oxbow lake and the adjacent river channel. To that end, water and macroinvertebrate samples were taken every 2 months in 2006. Ground movements during construction, wind‐driven bottom resuspension, shore scouring, and lack of vegetation resulted in distinctive water chemistry in the constructed and natural lakes. Regarding biodiversity, only 8 months after the digging of the constructed lake the abundance, richness, Shannon, and trait diversity of macroinvertebrates exceeded that of the natural lake. It is suggested that the constructed lake provided habitat for new mobile species that rapidly dispersed to other wetlands, thus enhancing the biological diversity of the floodplain at a local scale. Furthermore, biodiversity is predicted to continue increasing in the following years, although isolation can lead to early clogging of the system. By showing a dramatic increase in aquatic biodiversity in constructed wetlands, our study suggests that wetland construction can be very effective in mitigating habitat loss and increasing biodiversity in highly degraded floodplain areas. Further monitoring is nevertheless needed to evaluate the sustainability of the newly created habitat in the long term.     

Protist Biodiversity and Biogeography in Lakes From Four Brazilian River–Floodplain Systems

The biodiversity and biogeography of protists inhabiting many ecosystems have been intensely studied using different sequencing approaches, but tropical ecosystems are relatively under‐studied. Here, we sampled planktonic waters from 32 lakes associated with four different river–floodplains systems in Brazil, and sequenced the DNA using a metabarcoding approach with general eukaryotic primers. The lakes were dominated by the largely free‐living Discoba (mostly the Euglenida), Ciliophora, and Ochrophyta. There was low community similarity between lakes even within the same river–floodplain. The protists inhabiting these floodplain systems comprise part of the large and relatively undiscovered diversity in the tropics.     

The Structure of Bacterial Complexes in the Protva River Floodplain

The synecological analysis of bacterial communities from the Protva River floodplain biogeocenosis showed that all of their horizons contain spirilla, which are typical hydrobionts, and pigmented coryneform bacteria associated with the herbaceous plants of the floodplain meadows. The alluvial meadow soils of the inundated regions of the floodplain differ from the unflooded regions of the floodplain in that they have a more diverse bacterial population that is continuously distributed over the soil profile.     

Spatial and Temporal Trade-Offs by Bluegills in Floodplain River Ecosystems

Ecological trade-offs by organisms to minimize mortality and maximize growth is a foundational theme in ecology. Yet, these trade-offs are rarely examined within spatially complex, temporally variable ecosystems, such as floodplain rivers. Here, we evaluate ecological trade-offs across space and time for the bluegill (Lepomis macrochirus) in two unregulated river ecosystems in southeastern USA. Life-history differences among spatially segregated main channel and floodplain lake populations were used to assess effects of habitat type on bluegill fitness. Growth, condition, and gonadal somatic index were all significantly enhanced in floodplain lakes relative to the main channel. Furthermore, stomach fullness was significantly higher, and predator densities significantly lower in floodplain lakes thereby providing an ecological explanation for the life-history plasticity observed across the riverscape. However, historical observations suggested that although floodplain lakes are highly productive for bluegills, they are also prone to complete desiccation by drought approximately every 5 years, revealing the ultimate value of channel habitat, which does not dry, as desiccation refugia. Bluegills are faced with a balancing act associated with variation in foraging opportunities, and risks to predation and desiccation, that change in both the temporal and the spatial dimensions of floodplain rivers. The differential responses to these opportunities and risks help to explain why both habitats remain actively populated by bluegills, as well as many other organisms, in these and many other natural rivers.     

How Effective Are Biodiversity Conservation Payments in Mexico?

We assess the additional forest cover protected by 13 rural communities located in the southern state of Chiapas, Mexico, as a result of the economic incentives received through the country''s national program of payments for biodiversity conservation. We use spatially explicit data at the intra-community level to define a credible counterfactual of conservation outcomes. We use covariate-matching specifications associated with spatially explicit variables and difference-in-difference estimators to determine the treatment effect. We estimate that the additional conservation represents between 12 and 14.7 percent of forest area enrolled in the program in comparison to control areas. Despite this high degree of additionality, we also observe lack of compliance in some plots participating in the PES program. This lack of compliance casts doubt on the ability of payments alone to guarantee long-term additionality in context of high deforestation rates, even with an augmented program budget or extension of participation to communities not yet enrolled.     

Biodiversity of Jinggangshan Mountain: The Importance of Topography and Geographical Location in Supporting Higher Biodiversity

Diversity is mainly determined by climate and environment. In addition, topography is a complex factor, and the relationship between topography and biodiversity is still poorly understood. To understand the role of topography, i.e., altitude and slope, in biodiversity, we selected Jinggangshan Mountain (JGM), an area with unique topography, as the study area. We surveyed plant and animal species richness of JGM and compared the biodiversity and the main geographic characteristics of JGM with the adjacent 4 mountains. Gleason’s richness index was calculated to assess the diversity of species. In total, 2958 spermatophyte species, 418 bryophyte species, 355 pteridophyte species and 493 species of vertebrate animals were recorded in this survey. In general, the JGM biodiversity was higher than that of the adjacent mountains. Regarding topographic characteristics, 77% of JGM’s area was in the mid-altitude region and approximately 40% of JGM’s area was in the 10°–20° slope range, which may support more vegetation types in JGM area and make it a biodiversity hotspot. It should be noted that although the impact of topography on biodiversity was substantial, climate is still a more general factor driving the formation and maintenance of higher biodiversity. Topographic conditions can create microclimates, and both climatic and topographic conditions contribute to the formation of high biodiversity in JGM.     

Seasonality of a Floodplain Subsidy to the Fish Community of a Large Temperate River

Ecosystems - This study examines the temporal and spatial variability of the floodplain trophic contribution to the fish community of Lake Saint-Pierre, a large (≈ 300&nbsp;km2),...     

A cumulative impact management plan for a forested wetland watershed in the Mississippi River Floodplain

A management plan using a watershed-scale approach was devised to limit loss of wetland functions in the one million ha Tensas Basin, Louisiana, U.S.A. Proposals to develop wetland areas are evaluated for their potential to affect the structure and function of the landscape as a whole. The plan required two prior steps. First, we assessed the structural and functional status of the landscape through time. Second, using the assessment, we formulated a set of environmental goals. The assessment indicated that the landscape is severely degraded; of the original forest, 85% has been lost, and the deforestation has negatively affected water quality and biota. Specific goals were devised to conserve remaining wetland resources and to restore functional integrity to the basin as a whole. On the basis of these two prior steps and principles of landscape ecology and conservation biology, we devised a plan that would establish two large tracts of bottomland forest (BLF) totaling 102 000 and 63 000 ha. These tracts would be established by reforesting about 1000 ha of corridors, primarily along streams, linking existing forest patches. In addition, set-back levees and man-made diversions would be incorporated to restore natural flooding to certain areas of remaining BLF. Existing wetlands would be prioritized on the basis of size and density of patches and placed in one of three management categories. Implementation of such a plan is possible under the present regulatory authority of U.S. federal government programs administered by regulatory agencies responsible for wetland protection.From a paper presented at the Third International Wetlands Conference, 19–23 September 1988, University of Rennes, France.     

Rapid Turnover and Edge Effects in Dung Beetle Assemblages (Scarabaeidae) at a Bolivian Neotropical Forest-Savanna Ecotone1

Habitat fragmentation and the widespread creation of habitat edges have recently stimulated interest in assessing the effects of ecotones on biodiversity. Ecotones, natural or anthropogenic, can greatly affect faunal movement, population dynamics, species interactions, and community structure. Few data exist, however, on insect community response to forest–savanna ecotones, a natural analog to anthropogenically cleared areas adjacent to forest. In this study, the abundance, total biomass, average individual biomass, and distribution of scarabaeine dung beetles were examined at a sharp tropical evergreen forest–savanna ecotone in Santa Cruz, Bolivia. The abundance, total biomass, and average individual biomass of dung beetles varied significantly across the forest, edge, and savanna habitats. Species richness (S_obs) also varied significantly across the three habitats, but statistical estimations of true species richness (S_est) did not. Habitat specificity of the dung beetles in this study was extremely high. Of the 50 most common species collected during the study, only 2 species were collected in both the forest and savanna habitats, signaling nearly complete community turnover in just a few meters. Strong edge effects were evidenced by the decline in abundance, total biomass, and species richness at the forest‐savanna boundary.     

Floodplain lake fish assemblages in the Amazon River: directions in conservation biology

The Neotropical region is renowned for its high biodiversity, and the Amazon River basin contains the highest number of fish species of any river system in the world. In recent years, habitat fragmentation and exploitation of biotic resources have threatened biological integrity and provoked to need for sustainable management and conservation of the Amazon River system. We studied 36 floodplain lakes along 2000 km of the Amazon River. The fish assemblages associated with flood forests are moderately diverse, with low species dominance and reduced populations. To detect nestedness of fish assemblage composition in floodplain lakes, a nested subset analysis was performed on species presence–absence. The incidence matrix (species × lakes) was maximally packed using the Nestedness Temperature Calculator software. The results of ranking lakes and species allow us to establish targets for conservation. Such strategy for sustainable management should be focused on maintaining the Amazonian biodiversity.     

Flood‐Pulse Effects on Zooplankton Assemblages in a River‐Floodplain System (Gemenc Floodplain of the Danube,Hungary)

We studied the structure and population dynamics of zooplankton assemblages in the water bodies (eu‐, para‐, plesiopotamal and conjunctive water bodies) of a temperate floodplain during flood events. Here we report differences in the species composition of these water bodies in the two stages of flood pulses: rising vs. receding. During the receding period the proportion of larger and tychoplanktonic species increased. Similarity among zooplankton assemblages of these floodplain water bodies increased during the rising and decreased during the receding period. Species richness, diversity and population density values of zooplankton assemblages increased during the receding period in all types of water bodies except the eupotamal. The guild ratio of rotifer assemblages showed characteristic, but somewhat ambiguous changes. We conclude that the hydrological regime affects the structure and dynamics of zooplankton assemblages on the floodplain. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Building a Beetle: How Larval Environment Leads to Adult Performance in a Horned Beetle

The link between the expression of the signals used by male animals in contests with the traits which determine success in those contests is poorly understood. This is particularly true in holometabolous insects such as horned beetles where signal expression is determined during metamorphosis and is fixed during adulthood, whereas performance is influenced by post-eclosion feeding. We used path analysis to investigate the relationships between larval and adult nutrition, horn and body size and fitness-related traits such as strength and testes mass in the horned beetle Euoniticellus intermedius. In males weight gain post-eclosion had a central role in determining both testes mass and strength. Weight gain was unaffected by adult nutrition but was strongly correlated with by horn length, itself determined by larval resource availability, indicating strong indirect effects of larval nutrition on the adult beetle’s ability to assimilate food and grow tissues. Female strength was predicted by a simple path diagram where strength was determined by eclosion weight, itself determined by larval nutrition: weight gain post-eclosion was not a predictor of strength in this sex. Based on earlier findings we discuss the insulin-like signalling pathway as a possible mechanism by which larval nutrition could affect adult weight gain and thence traits such as strength.     

Overlooked Mountain Rock Pools in Deserts Are Critical Local Hotspots of Biodiversity

BackgroundThe world is undergoing exceptional biodiversity loss. Most conservation efforts target biodiversity hotspots at large scales. Such approach overlooks small-sized local hotspots, which may be rich in endemic and highly threatened species. We explore the importance of mountain rock pools (gueltas) as local biodiversity hotspots in the Sahara-Sahel. Specifically, we considered how many vertebrates (total and endemics) use gueltas, what factors predict species richness, and which gueltas are of most priority for conservation. We expected to provide management recommendations, improve local biodiversity conservation, and simultaneously contribute with a framework for future enhancement of local communities’ economy. The identification of local hotspots of biodiversity is important for revaluating global conservation priorities.Conclusion/SignificanceGueltas are crucial for local biodiversity conservation and human activities. They require urgent management plans in Mauritania’s mountains. They could provide refugia under climate change being important for long-term conservation of Sahara-Sahel biodiversity. Given their disproportional importance in relation to their size, they are local hotspots of biodiversity deserving global attention.     

Dung Beetle Community and Functions along a Habitat-Disturbance Gradient in the Amazon: A Rapid Assessment of Ecological Functions Associated to Biodiversity

Although there is increasing interest in the effects of habitat disturbance on community attributes and the potential consequences for ecosystem functioning, objective approaches linking biodiversity loss to functional loss are uncommon. The objectives of this study were to implement simultaneous assessment of community attributes (richness, abundance and biomass, each calculated for total-beetle assemblages as well as small- and large-beetle assemblages) and three ecological functions of dung beetles (dung removal, soil perturbation and secondary seed dispersal), to compare the effects of habitat disturbance on both sets of response variables, and their relations. We studied dung beetle community attributes and functions in five land-use systems representing a disturbance gradient in the Brazilian Amazon: primary forest, secondary forest, agroforestry, agriculture and pasture. All response variables were affected negatively by the intensification of habitat disturbance regimes, but community attributes and ecological functions did not follow the same pattern of decline. A hierarchical partitioning analysis showed that, although all community attributes had a significant effect on the three ecological functions (except the abundance of small beetles on all three ecological functions and the biomass of small beetles on secondary dispersal of large seed mimics), species richness and abundance of large beetles were the community attributes with the highest explanatory value. Our results show the importance of measuring ecological function empirically instead of deducing it from community metrics.     

Feasibility of Estimating Cu Contamination in Floodplain Soils using VNIR Spectroscopy—A Case Study in the Le’an River Floodplain,China

Heavy metal accumulation can influence the physical, chemical, and ecological processes in the soil ecosystem, and the accumulation of heavy metals has become a serious environmental issue in China, especially in the floodplains downstream from mining and smelting sites. A novel method of estimating the heavy metal contamination of soil is proposed using visible and near-infrared (VNIR) spectroscopy and partial least squares regression (PLSR). Our study focuses on the Le’an river floodplain, Jiangxi Province, China, which houses the largest copper mining operation in China and has suffered a series of environmental setbacks from the extraction of copper. Our study employs PLSR to summarize the relationship between VNIR reflectance spectra and the copper content of collected soil samples, and then estimates copper contamination of the soil using VNIR spectroscopy and the calibrated model. More specifically, with 71 soil samples collected from the Le’an River floodplain, our study aims at (1) exploring the correlation between VNIR and soil constituents, including soil organic matter, total copper, and iron content; (2) assessing the relationship between VNIR determination of copper and the pre-processing of soil samples; and (3) evaluating the performance of data transformation methods in PLSR. The correlation analysis revealed that the mechanism of estimating Cu content lay in its correlation with Fe content. The PLSR model with logarithmic scale transformed copper content and the standard normal variate spectra was chosen for estimating copper contamination from untreated soil samples; the model with logarithmic scale transformed copper content and reflectance spectra was selected for pretreated soil samples. The correlation analyses and regression results in the PLSR models both suggest that the main mechanism for estimating Cu content in this case study lies in its correlation with Fe content. Therefore, the coupling of VNIR spectroscopy and PLSR could serve as an alternative method of monitoring heavy metal contamination of soil.     

Are Infaunal Predators Important in Structuring Marine Soft-Bottom Communities?

The role of infaunal predators in structuring marine soft-bottomcommunities was evaluated according to these predators': 1)effects on prey density based on manipulative field experiments,2) feeding rates, 3) effects on prey distribution, 4) effectson species diversity, and 5) interactions with their prey. Estimatesof feeding rates indicate that many predatory taxa have thepotential to reduce the size of prey populations and suggestthat nemerteans are likely to have a larger impact on infaunalabundances than polychaetes. Infaunal predators have been demonstratedto have a significant effect on infaunal densities and to affectthe spatial and temporal distribution of their prey. The effectsof these predators on species diversity apparently depend onthe predator and the diversity of the system. These conclusionsmay not be applicable to all soft-bottom habitats or all groupsof infaunal predators because they are based on studies of veryfew taxa conducted almost exclusively in intertidal, unvegetated,mud habitats. Additional studies are needed on the effects ofpredation by infauna on infaunal population dynamics and onthe mechanisms of interactions between predator and prey. Furtherinvestigation will probably reveal that different groups ofinfaunal predators play different roles in structuring soft-bottomcommunities.